Older Age as a Predictor of Ongoing Active Changes in Follow-Up Cardiac Magnetic Resonance in Children with Acute Myocarditis

Abstract

Background/Objectives: Cardiac magnetic resonance (CMR) is used to diagnose and monitor the course of acute myocarditis in adults and children. This study aimed to assess the frequency of persistent inflammation at follow-up CMR and to look for predictors of ongoing active changes in CMR in children with myocarditis. Methods: This retrospective study included 31 children (median age 15 years, 68% male) with clinically and CMR-diagnosed acute myocarditis who underwent baseline and follow-up CMR at a median of 6 months. Old and new Lake Louise criteria were compared. Results: A complete resolution of changes was observed in four patients (13%) at follow-up, according to both criteria. Seven patients (23%) presented ongoing active changes, and twenty (64%) showed a persistent scar according to the old Lake Louise criteria. When the new Lake Louise criteria were used, an additional two patients (6%) were found to have persistent active changes instead of a persistent scar. Patients with persistent inflammation (nine patients, 29%) were older than those who showed recovery. None of the patients below 14 years of age presented active changes on their follow-up CMR and all the patients who showed inflammation were between 14 and 17 years old. Conclusions: Pediatric myocarditis can lead to persistent active changes in CMR beyond a 6-month follow-up in over a fifth of patients. The application of new Lake Louise criteria further increases that number compared to the old criteria. The only predictor of persistent inflammatory changes in CMR is older age.